GMC 2010 T-Series Owner's Manual page 257

(10) = Chassis Lubrication Service: Lubricate all grease
fittings in front suspension, front axle, and steering
linkage. Do not lubricate kingpin bushings with air
pressure equipment; instead, use a hand grease gun
to ensure complete purge and eliminate sealer cap
distortion. Front axle tie rod ends, both upper and lower
kingpin fittings, and both steering linkage relay rod
ends should be greased with the vehicle loaded on the
ground and wheels turned straight ahead, not with the
vehicle on a hoist. Apply kingpin bushing lubricant to
both upper and lower kingpin grease fittings until new
lubricant purges from between the upper shim pack and
thrust bearing. Lubricate transmission and shift linkage,
tilt cab hinges and latches, parking brake lever pivot,
clevis pins and linkage, disc brake caliper rails, bearing
pads, propshaft universal joints, brake camshaft
bracket, slack adjusters, and pedal shaft. Lubricate
suspension, axle, and steering linkage more often when
operating under dusty or muddy conditions and in
excessive off-road use. Frequently power-washed
vehicles will require more frequent lubrication.
(11) = Check steering system:
Look for damaged, loose, or missing parts. Inspect
the steering linkage relay rod and tie rod ends for
looseness or lack of lubricant. Also look for parts
showing signs of wear or lack of lubrication.
Replace parts as needed. Also check steering gear
mounting bolts, pitman arm nut, gear housing
upper cover and side cover attaching bolts,
steering column mounting bolts, and cardan joint
clamp bolts; tighten if necessary. See the service
manual.
Inspect power steering hoses, tubes, and fittings
for leaks. Hoses and lines must not be twisted,
kinked, or tightly bent. Make sure clips, clamps,
supporting tubes, and hoses are in place and
properly secured.
Check steering gear for leakage around pitman
shaft and housing. If leakage is evident (lubricant
oozing out, not just oily film), leak should be
corrected immediately.
(12) = Check front and rear suspension. Look for
damaged, loose or missing parts or parts showing signs
of wear or lack of lubrication. Replace parts as needed.
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